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ABSTRACT Objective: Hemangioblastoma is a rare vascular sporadically occurring CNS tumor that can be associated with von Hippel-Lindau disease. Hemangioblastomas account for 2-6% of all spinal cord neoplasms and rank third among intramedullary space-occupying lesions. Methods: This was the first time in our practice that we had dealt with paravertebral hemangioblastoma with the sandglass growth pattern. The world literature describes only 3 case of a tumor with this growth pattern. Surgical and diagnostic aspects of patient treatment are considered. Results: During the operation, we adhered to the following stages: localization of the feeding vessel and of the poles of the tumor, surface dissection of the tumor, en bloc resection of the tumor, and hemostasis of the tumor cavity. Conclusions: Hemangioblastoma of extradural localization is a very rare pathology. However, when MRI signs characteristic of a vascular lesion are identified, it is necessary to carry out additional examinations, which may include CT perfusion study and, if required, selective angiography. Level of Evidence 5; Case report.

RESUMO Objetivos: Hemangioblastoma é um tumor vascular raro do SNC, que ocorre esporadicamente e pode ser associada à doença de Von Hippel-Lindau. Hemangioblastomas são responsáveis por 2-6% de todas as neoplasias da medula espinal e na terceira posição entre lesões, ocupando espaço intramedulares da medula espinal. Métodos: Foi a primeira vez em nossa prática que lidamos com hemangioblastoma paravertebral com o padrão de crescimento ampulheta. As fontes da literatura mundial descrevem apenas 3 casos de um tumor com esse padrão de crescimento. Aspectos cirúrgicos e diagnósticos de tratamentos do paciente são considerados. Resultados: Durante a operação, aderiu-se às seguintes fases: o recipiente de alimentação foi encontrado, os pólos do tumor foram encontrados, a dissecação da superfície do tumor foi feita, o tumor foi removido por um único bloco e a hemostasia da cavidade do tumor foi realizada. Conclusões: Hemangioblastoma de localização extradural é uma patologia muito rara, no entanto, quando sinais de MRI característicos de uma lesão vascular são identificados, o que é necessário para levar a cabo um exame suplementar, o qual pode incluir o estudo de perfusão CT e, se necessário, angiografia seletiva. Nível de Evidência V; Relato de caso.

RESUMEN Objetivo: El hemangioblastoma es un tumor vascular raro del SNC que ocurre esporádicamente y que puede asociarse con la enfermedad de von Hippel-Lindau. Los hemangioblastomas representan el 2%-6% de todas las neoplasias de la médula espinal y están en el tercer lugar entre las lesiones intramedulares que ocupan espacio. Métodos: Esta fue la primera vez en nuestra práctica que tratamos el hemangioblastoma paravertebral con patrón de crecimiento de reloj de arena. La literatura mundial describe solo tres casos de un tumor con este patrón de crecimiento. Se consideran aspectos quirúrgicos y de diagnóstico del tratamiento del paciente. Resultados: Durante la operación, elegimos las siguientes etapas: localización del vaso de irrigación y de los polos del tumor, disección superficial del tumor resección en bloque del tumor y hemostasia de la cavidad tumoral. Conclusiones: El hemangioblastoma de localización extradural es una patología muy rara. Sin embargo, cuando se identifican signos característicos de lesión vascular en la RM, es necesario realizar exámenes adicionales, que pueden incluir estudio de perfusión por TC y, si es necesario, una angiografía selectiva. Nivel de Evidencia V; Reporte de caso.

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The mechanisms underlying cardiac fibrillation have been investigated for over a century, but we are still finding surprising results that change our view of this phenomenon. The present study focuses on the transition from normal rhythm to spiral wave chaos associated with a gradual increase in the pacing rate. While some of our findings are consistent with existing experimental, numerical, and theoretical studies of this problem, one result appears to contradict the accepted picture. Specifically we show that, in a two-dimensional model of paced homogeneous atrial tissue, transition from discordant alternans to conduction block, wave breakup, reentry, and spiral wave chaos is associated with the transient growth of finite amplitude disturbances rather than a conventional instability. It is mathematically very similar to subcritical, or bypass, transition from laminar fluid flow to turbulence, which allows many of the tools developed in the context of fluid turbulence to be used for improving our understanding of cardiac arrhythmias.

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Background: Problems associated with alcohol consumption are prevalent in Chile, but little is known about the situation in the elderly. Aim: To perform a screening to detect alcohol-related problems and risks in the Chilean older people who travel. Material and Methods: The Alcohol Use Disorders Identification Test (AUDIT) questionnaire was answered by 1,076 travelers aged 60 to 93 years (66% females), who participated in trips organized by the Chilean National Tourism Service (SERNATUR). Results: Seventy six percent of respondents acknowledged to have ingested an alcoholic drink during the last month. The average AUDIT score was of 2.2 ± 2.6. Only 3.7% of the sample had a score equal or higher than eight, considered as risky use. Within this last group, 60% had symptoms of alcohol dependence. A higher alcohol consumption was associated with male gender (p < 0.01), being younger than 75 years of age (p < 0.01), having a medium-low economic income (p < 0.01) and having a higher education level (p = 0.03). There was no significant association with the respondents´ occupation. Conclusions: In this sample of Chilean traveling older people, there was a high prevalence of alcohol consumption, and nearly 4% of respondents had alcohol related problems.

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Alternans-an arrhythmic response of cardiac tissue to periodic pacing-often serves as a precursor to a more dangerous, and potentially lethal, state of fibrillation. Suppression of alternans using feedback control may be a plausible method to prevent fibrillation. Several approaches based on impulsive control have been proposed previously, where feedback is applied for a brief instance of time during each pacing interval. This paper presents a continuous-time approach, where feedback current is applied at all times, which is capable of suppressing alternans in fibers of significantly greater length (up to at least 4 cm), compared with impulsive control (less than 1 cm), and for a wide range of pacing cycle lengths.

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BACKGROUND: A reduction in long-term survival of adult patients hospitalized with community-acquired pneumonia (CAP), especially older people with múltiple comorbidities, has been reported. AIM: To examine the clinical variables associated to mortality at 72 months of adult patients older than 60 years hospitalized with CAP and compare their mortality with a control group matched for age, gender and place of admission. MATERIAL AND METHODS: Prospective assessment of 465 immunocompetent patients aged 61 to 101 years, hospitalized for CAP in a teaching hospital. Hospital and 30 day mortality was obtained from medical records. Seventy two months survival of the 424 patients who were discharged olive, was compared with a group of 851 patients without pneumonia paired for gender and age. Mortality at 72 months was obtained from death certificates. RESULTS: Eighty seven percent of patients had comorbidity. The median hospital length of stay was 10 days, 8.8% died in the hospital, 29.7% at one year follow-up and 61.9%o at 6 years. The actuarial survival at six years was similar in the cohort of adults hospitalized with CAP and the control group matched for age, gender and site of care. In a multivariate analysis, the clinical variables associated with increased risk of dying during long-term follow-up were older age, chronic cardiovascular and neurological diseases, malignancy, absence of fever, low C-reactive protein at hospital admission and high-risk parameters of the Fine índex. CONCLUSIONS: Advanced age, some specific comorbidities, poor systemic inflammatory response at admission and high risk parameters of the Fine Index were associated to increased risk of dying on long-term follow-up among older adults hospitalized for CAP.

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Background: A reduction in long-term survival of adult patients hospitalized with community-acquired pneumonia (CAP), especially older people with múltiple comorbidities, has been reported. Aim: To examine the clinical variables associated to mortality at 72 months of adult patients older than 60 years hospitalized with CAP and compare their mortality with a control group matched for age, gender and place of admission. Material and Methods: Prospective assessment of 465 immunocompetent patients aged 61 to 101 years, hospitalized for CAP in a teaching hospital. Hospital and 30 day mortality was obtained from medical records. Seventy two months survival ofthe 424 patients who were discharged olive, was compared with a group of 851 patients without pneumonia paired for gender and age. Mortality at 72 months was obtained from death certificates. Results: Eighty seven percent of patients had comorbidity. The median hospital length ofstay was 10 days, 8.8% died in the hospital, 29.7% at one year follow-up and 61.9%o at 6 years. The actuarial survival at six years was similar in the cohort of adults hospitalized with CAP and the control group matched for age, gender and site of care. In a multivariate analysis, the clinical variables associated with increased risk of dying during long-term follow-up were older age, chronic cardiovascular and neurological diseases, malignancy, absence of fever, low C-reactive protein at hospital admission and high-risk parameters of the Fine índex. Conclusions: Advanced age, some specific comorbidities, poor systemic inflammatory response at admission and high risk parameters of the Fine Index were associated to increased risk of dying on long-term follow-up among older adults hospitalized for CAP.

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BACKGROUND: Mortality increases in adults, especially in older adults, after recovery from an episode of community-acquired pneumonia (CAP). AIM: To analyze survival and predictors of death at one year follow up of a cohort of adult patients hospitalized with CAP. MATERIAL AND METHODS: Immunocompetent patients admitted to a clinical hospital for an episode of CAP were included in the study and were assessed according to a standardized protocol. One year mortality after admission was assessed using death records of the National Identification Service. Clinical and laboratory variables measured at hospital admission associated with risk of death at one year follow up were subjected to univariate and multivariate analysis by a logistic regression model. RESULTS: We evaluated 659 patients aged 68 ± 19 years, 52% were male, 77% had underlying conditions (especially cardiovascular, neurological and respiratory diseases). Mean hospital length of stay was 9 days, 7.1% died during hospital stay and 15.8% did so during the year of follow-up. A causal agent was identified in one third of cases. The main pathogens isolated were Streptococcus pneumoniae (12.9%), Haemophilus influenzae (4.1%), respiratory viruses (6.5%) and Gram-negative bacilli (6.5%). In multivariate analysis, the clinical variables associated with increased risk of dying during the year of follow-up were older age, chronic neurological disease, malignancies, lack of fever at admission and prolonged hospital length of stay. CONCLUSIONS: Age, specific co-morbidities such as chronic neurological disease and cancer, absence of fever at hospital admission and prolonged hospital length of stay were associated with increased risk of dying during the year after admission among adult patients hospitalized with community-acquired pneumonia.

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Background: Mortality increases in adults, especially in older adults, after recovery from an episode of community-acquired pneumonia (CAP). Aim: To analyze survival and predictors of death at one year follow up of a cohort of adult patients hospitalized with CAP. Material and Methods: Immunocompetent patients admitted to a clinical hospital for an episode of CAP were included in the study and were assessed according to a standardized protocol. One year mortality after admission was assessed using death records of the National Identification Service. Clinical and laboratory variables measured at hospital admission associated with risk of death at one year follow up were subjected to univariate and multivariate analysis by a logistic regression model. Results: We evaluated 659 patients aged 68 ± 19 years, 52% were male, 77% had underlying conditions (especially cardiovascular, neurological and respiratory diseases). Mean hospital length of stay was 9 days, 7.1% died during hospital stay and 15.8% did so during the year of follow-up. A causal agent was identified in one third of cases. The main pathogens isolated were Streptococcus pneumoniae (12.9%), Haemophilus influenzae (4.1%), respiratory viruses (6.5%) and Gram-negative bacilli (6.5%). In multivariate analysis, the clinical variables associated with increased risk of dying during the year of follow-up were older age, chronic neurological disease, malignancies, lack of fever at admission and prolonged hospital length of stay. Conclusions: Age, specific co-morbidities such as chronic neurological disease and cancer, absence of fever at hospital admission and prolonged hospital length of stay were associated with increased risk of dying during the year after admission among adult patients hospitalized with community-acquired pneumonia.

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BACKGROUND: Among hypertensive patients, other risk factors for mortality and morbidity, besides blood pressure, must be considered when therapeutic decisions are done. AIM: To assess the incidence and relevance of cardiovascular risk factors in a cohort of patients with essential hypertension. MATERIAL AND METHODS: A cohort of 1,072 treated patients with essential hypertension was followed for a period up to 25 years. Four hundred eighty six were men and 586 were women, age ranged from 31 to 70 years. At entry, 56% of subjects did not have any organic complications associated to hypertension (stage I WHO criteria), 30% had mild alterations (Stage II) and 14% had major complications (myocardial infarction, stroke, heart failure or renal failure). Likewise, 43.8% had mild, 14.5%, moderate and 41.7%, severe hypertension. Patients were treated with monotherapy or combined therapy based on diuretics, beta blockers, calcium antagonists and angiotensin converting enzyme inhibitors. Goal of therapy was 140/90 mm Hg. Risk factors associated diseases and complications were registered carefully. Causes of death were obtained from hospital records and death certificates. Mortality was analyzed using life tables (intention to treat method included). RESULTS: Blood pressure dropped significantly during follow up from a mean of 182/110 to 154/92 mm Hg. During follow up, 143 patients died and 429 complications (lethal or non lethal) were recorded. Twenty four percent of patients smoked, 24% reported alcohol intake, 56% had hypercholesterolemia, 11% were obese, 13% had diabetes and 3% had gout. The proportional hazard model showed that the existence of previous complications, the presence of more than 3 risk factors, and age over 60 and mean systolic and diastolic pressure during therapy, were independent and significant risk factors for mortality. CONCLUSIONS: The incidence of risk factors among our hypertensive patients is very similar to that of other national or international cohorts.

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BACKGROUND: Third generation beta blockers have an intrinsic simpatico-mimetic activity and are cardioselective. Therefore, they should not have adverse bronchial effects and could even have a slight bronchodilator activity. AIM: To test the efficacy and safety of celiprolol in hypertensive patients with chronic obstructive lung disease. PATIENTS AND METHODS: Uncomplicated hypertensive patients with chronic obstructive lung disease received celiprolol during 12 weeks. They were subjected to monthly clinical assessment and ventilatory function was measured on the basal period and at the end of the trial. RESULTS: During the study period, blood pressure fell significantly from 179 +/- 6/112 +/- 8 to 161 +/- 4.7/98 +/- 1.6 mmHg. No changes were observed in forced expiratory volume in 1 s or in forced expiratory flow between 25 and 75% of the vital capacity. No subjective changes in respiratory function were reported during the trial. CONCLUSIONS: No changes in ventilatory function were observed in these patients with chronic obstructive lung disease, treated with celiprolol during 12 weeks.

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BACKGROUND: Policosanol is a new cholesterol lowering agent derived from sugar cane. AIM: To compare the cholesterol lowering efficacy of policosanol with HMG CoA inhibitors. PATIENTS AND METHODS: Patients with a LDL cholesterol over 160 mg/dl were studied. If, after 6 weeks of diet, cholesterol persisted elevated, they were doubly blind randomized to receive policosanol 10 mg/day (55 patients), lovastatin 20 mg/day (26 patients) or simvastatin 10 mg/day (25 patients). Serum cholesterol was measured again after 8 weeks of therapy. RESULTS: Initial demographic and laboratory data were similar among treatment groups. A 24% LDL cholesterol reduction was obtained with policosanol, compared with a 22% reduction with lovastatin and a 15% reduction with simvastatin. HDL cholesterol significantly increased in patients on policosanol and did not change in the other treatment groups. Adverse effects of policosanol were mild and unspecific. No changes in hepatic enzymes were observed. CONCLUSIONS: Policosanol is a safe and effective cholesterol reducing agent.

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This review describes the most recent advances in the treatment of essential hypertension, from non pharmacological measures and changes in lifestyles to new blood pressure lowering drugs. A blood pressure lower tha 130/80 mmHg, has been established as the new goal for optimal treatment. In the last two consensus a new range of blood pressure, denominated "high normal" (130-139/85-89 mm Hg) has been incorporated. People with other cardiovascular risk factors and a blood pressure within this range, should be treated. The HOT study recently demonstrated that a reduction to less than 90 mmHg of diastolic pressure is associated with a reduction on cardiovascular morbidity and mortality. The importance of the peak/valley relationship in the election of anti hypertensive medication is also reviewed.

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There is a group of genetic alterations that are phenotypically related to mineralocorticoid hypertension. They include, among others, some forms of primary hyperaldosteronism and of hyporeninemic aldosteronism that can be specifically treated, thus becoming secondary forms of hypertension. These could account for 10 to 15% of cases of essential hypertension, but more studies are required to accept these figures. The screening for these forms of hypertension should be done measuring aldosterone levels and plasma renin activity. An aldosterone/plasma renin activity ratio over 25 should lead to the suspicion of the disease. However, the cost effectiveness of the widespread measurement of these parameters would be very low. Therefore it is mandatory to determine the epidemiological features of these diseases to perform a selective screening among subjects with essential hypertension.

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Continuous ambulatory blood pressure monitoring is a diagnostic technique devised as a consequence of the great variations in blood pressure measurements. It allows multiple daily measurements, nocturnal monitoring, avoids the stress of blood pressure measurements, gives a picture of pressure behavior during 24 hours and reduces observer related errors. The equipment used must be accurate and validated using international protocols. Accepted indications for continuous ambulatory blood pressure monitoring are white coat hypertension, episodic hypertension, resistance to medications and assessment of symptoms or autonomic dysfunction. Other indications with less clear cut usefulness, are high risk cardiac, renal or pregnant patients and an accurate blood pressure control. We describe equipment calibration, elements that must be considered in the reports, result interpretation and conclusions. Normal blood pressure ranges for children and pregnant women are also reported.

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BACKGROUND: The V JNC consensus stated that although new antihypertensive agents, such as angiotensin converting enzyme inhibitors and calcium channel blockers, are considered safer drugs, there is no firm evidence from large controlled trials that these drugs are associated with a lower cardiovascular mortality. AIM: To study the association between cardiovascular risk factors, blood pressure levels, pharmacological treatment and mortality in a group of hypertensive patients followed at an hypertension outpatient clinic. PATIENTS AND METHODS: Patients with essential hypertension were treated with different antihypertensive medications, according to physicians criteria, and controlled until death or loss from follow up. Causes of death were obtained from hospital records and death certificates. Survival was analyzed using life tables, comparisons between groups of patients were done using chi square or a Cox's proportional hazards model. RESULTS: Three hundred thirty-nine hypertensive patients aged 33 to 80 years old were followed for a mean period of 9.8 +/- 4.9 years. Eighty-six were treated with beta blockers, 64 with diuretics, 133 with calcium antagonists and 56 with ACE inhibitors. Blood pressure dropped similarly with all medications. During follow up, 79 patients died. Life table analysis showed that patients with a history of angina, diabetes or myocardial infarction had higher mortality rates. Similarly, patients treated with beta blockers and diuretics had higher mortality than patients treated with calcium antagonists or angiotensin converting enzyme inhibitors. The proportional hazards model showed that the effect of treatment modality persisted after correction for the other risk factors for mortality. CONCLUSIONS: In this series of hypertensive patients, those treated with beta blockers or diuretics had higher mortality rates than those receiving calcium channel antagonists or angiotensin converting enzyme inhibitors.

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Prospective, randomized and long term multicentric studies, published since 1988, on the effects of pharmacological or non pharmacological treatment of hypertension are analyzed. Former studies, performed between 1967 and 1987, are devoted, in chronological order, to special populations or to forms of hypertension not sufficiently studied previously (elders and isolated systolic hypertension), using classical pharmacological treatments such as diuretics and beta blockers. Their results confirm the reduction in mortality obtained using such therapies. Ensuing studies, focused on the analysis of new drugs such as calcium antagonists and angiotensin converting enzyme inhibitors, also demonstrated a reduction in cardiovascular risk, even in severely damaged populations. Thereafter, meta analysis of new pharmacological treatments and of non pharmacological therapies such as sodium restriction, weight reduction, avoidance of alcohol intake, calcium and potassium supplementation have appeared. These studies have emphasized the importance of prevention through changes in lifestyles. Their positive, although modest results, encourage the assessment of long term preventive and therapeutic measures in hypertension.

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BACKGROUND: In the last two decades, angiotensin converting enzyme inhibitors have become first line medications in the treatment of hypertension. AIM: To assess the tolerance and effectiveness of ramipril as monotherapy in the treatment of essential hypertension. PATIENTS AND METHODS: One hundred eighty eight hypertensive patients, aged 21 to 80 years-old, coming from 4 Chilean hospitals were studied. Using an open non controlled design; they were treated with placebo for two weeks and with the active drug during eight weeks, in initial doses of 2.5 mg/day that were adjusted to 5 mg/day if diastolic blood pressure did not drop below 90 mm Hg or if its reduction was less than 10 mm Hg. RESULTS: During the active drug treatment period, systolic blood pressure decreased from 164.8 +/- 7.2 to 147.3 +/- 4.8 mm Hg. Diastolic blood pressure dropped from 102.3 +/- 3.1 to 87.8 +/- 3.0 mm Hg. Seventy percent of patients achieved a diastolic blood pressure of less than 90 mm Hg, 56.9% with 2.5 mg/day and 13.8% with 5 mg/day. Dizziness, cough and headache were the main adverse reactions, observed in 3.7, 3.2 and 2.1% of patients respectively. Adherence to treatment was 98%. There were no changes in laboratory values during the treatment period. CONCLUSIONS: Ramipril is effective and well tolerated in the treatment of essential hypertension.

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Early studies of the seventies and eighties showed an inverse relationship between blood pressure reduction and incidence of complications and death. Afterwards, in the late eighties, some authors showed that reductions of diastolic blood pressure beyond 85 or 90 mm Hg increased coronary heart disease mortality (J shaped curve). Meta-analyses and recent epidemiological studies have shown that cardiovascular morbidity decreases along with reductions in diastolic blood pressure, if it is kept within normal limits (70-89 mm Hg). Cardiovascular mortality decreases significantly with blood pressure reductions of 7 to 8 mmHg. Some authors have suggested that diastolic blood pressure should be reduced to 85 mmHg or less in individuals with several cardiovascular risk factors, to obtain a better risk reduction. This hypothesis waits for confirmation from follow-up studies.

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Insulin resistance is associated to hypertension, obesity and diabetes and may be an independent cardiovascular risk factor. The exact assessment of insulin resistance requires complex metabolic studies. However, there is a good correlation between this parameter and fasting serum insulin levels. The aim of this work was to study fasting serum insulin levels by radio immuno analysis in 43 hypertensive patients aged 56 +/- 5.5 years old (27 male, 17 obese and 8 diabetics) and 20 normotensive controls aged 50 +/- 4.8 years old (13 male). Insulin levels were 3.8 UI/L in controls, 12.1 UI/L in normal weight, 15.5 UI/L in obese and 18.3 UI/L in diabetic hypertensives (ANOVA p < 0.001). These levels were above two standard deviations of control values in 50% of normal weight, 66% of obese and 62% of diabetic hypertensives. It is concluded that normal weight, obese and diabetic hypertensive subjects have high fasting insulin levels.

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The classic concept of a direct pathogenic relationship between high blood pressure and development of left ventricular hypertrophy has been challenged by observations such as the modest correlations between blood pressure and magnitude of left ventricular hypertrophy, its frequent reversal with some antihypertensive medications and its experimental prevention with low doses of an angiotensin-converting enzyme inhibitor that do not modify blood pressure. This evidence has prompted the revision of mechanisms or factors involved in the development of left ventricular hypertrophy. The roles of sympathetic nervous and renin-angiotensin systems, genetic and endothelial factors, are reviewed in this article. It is concluded that blood pressure is not the sole responsible for left ventricular hypertrophy, but an epiphenomenon of one or more local or tissular mechanisms, primary or unchained by an unknown genetic factor.

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